Air Corp

Received enlistment and seperation record and trying to figure it out for my son's grandfather. He was in the 120th AAF Base Unit from Westover Field that was in Australia from March 1942 to December 1944. His military occupation is blurred, the number is 301,it may be munition burker? Can anyone explain what that is? In the remarks it states: issued lapel button, 23 days lost under --(can't read)107 ASR score 112 2 Sep 45. Does this make sense?His grade was Sgt at separation, he had been in the Army 240th CAC for almost 1 year before the Air Corp. He died in 1995 and had not been in contact with his son or grandsons for many years. Trying to decipher this information so they do not forget. Thank you for any help.